Magnetorheological damping device for reduction or elimination of vibration in steering systems

• US 20070137955A1
• Filed: 11/02/2005
• Published: 06/21/2007
• Est. Priority Date: 11/02/2005
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Ginder, John, Schmidt, Joe, Giese, Dieter, Maranville, Clay
• Granted Patent: US 7,823,708 B2
• Time in Patent Office: Days
• US Class Current: 188/267.200
• CPC Class Codes: B62D 7/224 acting between the steering wheel and the steering gear, e.g. on the steering column
• CPC Class Codes: F16F 9/535 Magnetorheological [MR] fluid dampers springs comprising magnetorheological [MR] elastomers F16F1/361

Abstract

A damping device for use with a rotatably-mounted steering shaft. The damping device comprises a magnetorheological material that can be embedded in an open-network carrier and is directly or indirectly in contact with the steering shaft, a coil arranged in effective proximity to the magnetorheological material, and a body indirectly in contact with the steering shaft through the magnetorheological material, which does not rotate with the steering shaft. A voltage can be applied the coil to activate the magnetorheological material, increasing a viscosity of the magnetorheological material to inhibit relative rotation of the steering shaft and the body.

Claims

1. A damping device for use with a rotatably-mounted steering shaft, the damping device comprising:

a magnetorheological material embedded in an open-network carrier and directly or indirectly in contact with the steering shaft;

a coil arranged in effective proximity to the magnetorheological material; and

a body indirectly in contact with the steering shaft through the magnetorheological material, and which does not rotate with the steering shaft,

wherein a voltage applied to the coil to activate the magnetorheological material increases a viscosity of the magnetorheological material to inhibit relative rotation of the steering shaft and the body.

2. The damping device of claim 1, wherein the body is fixed external to the steering shaft so that it does not rotate with the steering shaft.

3. The damping device of claim 1, further comprising a flux carrier in effective proximity to the coil.

4. The damping device of claim 3, wherein the flux carrier is positioned relative to the coil to make a magnetic field pass perpendicularly through the magnetorheological material.

5. The damping device of claim 4, further comprising a sleeve extending at least partially around the steering shaft that acts as a flux return path.

6. The damping device of claim 5, wherein the sleeve is positioned relative to the coil and the flux carrier to make the magnetic field pass perpendicularly through the magnetorheological material.

7. The damping device of claim 1, wherein the magnetorheological material comprises a cylindrical band surrounding the steering shaft.

8. The damping device of claim 7, wherein the magnetorheological material comprises magnetizable particles suspended in a suitable carrier.

9. A damping device for use with a rotatably-mounted steering shaft, the damping device comprising:

a magnetorheological material directly or indirectly in contact with the steering shaft, and having a viscosity such that seals are not needed to contain the magnetorheological material;

a coil arranged in effective proximity to the magnetorheological material; and

a body indirectly in contact with the steering shaft through the magnetorheological material, and which does not rotate with the steering shaft,

wherein a voltage applied to the coil to activate the magnetorheological material increases a viscosity of the magnetorheological material to inhibit relative rotation of the steering shaft and the body.

10. The damping device of claim 9, wherein the body is fixed external to the steering shaft so that it does not rotate with the steering shaft.

11. The damping device of claim 9, further comprising a flux carrier in effective proximity to the coil.

12. The damping device of claim 11, wherein the flux carrier is positioned relative to the coil to make a magnetic field pass perpendicular through the magnetorheological material.

13. The damping device of claim 12, further comprising a sleeve extending at least partially around the steering shaft that acts as a flux return path.

14. The damping device of claim 13, wherein the sleeve is positioned relative to the coil and the flux carrier to make the magnetic field pass perpendicular through the magnetorheological material.

15. The damping device of claim 9, wherein the magnetorheological material comprises a cylindrical band surrounding the steering shaft.

16. The damping device of claim 14, wherein the magnetorheological material comprises magnetizable particles suspended in a suitable carrier.

17. A damping device for use with a rotatably-mounted steering shaft, the damping device comprising:

a housing at least partially surrounding the steering shaft that does not rotate with the steering shaft;

a coil and a flux carrier fixedly attached to the housing at a radially outer position; and

a magnetorheological material extending between the coil and the steering shaft;

wherein a voltage applied to the coil to activate the magnetorheological material increases the viscosity of the magnetorheological material to inhibit rotation of the steering shaft, and

wherein seals are not needed to contain the MR material.

18. The damping device of claim 17, further comprising a disc-like bracket fixedly mounted around the steering shaft and a cylindrical sleeve fixedly mounted to the bracket at a radially outer position, the bracket and sleeve rotating with the steering shaft, wherein the magnetorheological material extends between the coil and the cylindrical sleeve.

19. The damping device of claim 17, wherein the coil and flux carrier are positioned to make a magnetic field pass perpendicularly through the magnetorheological material.

20. A method for damping vibrations in a rotatably-mounted steering shaft, comprising:

embedding a magnetorheological material in an open-network carrier and directly or indirectly placing the magnetorheological material in contact with the steering shaft;

arranging a coil in effective proximity to the magnetorheological material;

providing a body that does not rotate with the steering shaft, and which is in contact with the steering shaft through the magnetorheological material; and

applying a voltage to the coil to activate the magnetorheological material, increasing a viscosity of the magnetorheological material to inhibit relative rotation between the steering shaft and the body.